Method of manufacturing wetproof cellulose products



Patented Aug. 6, 1935. I

UNITED STATES PATENT OFFICE METHOD OF MANUFACTURING WETPROOF CELLULOSE PRODUCTS Julius Kantorowicz, Breslau, Germany No Drawing. Application September 4, 1931, fog-Sal No. 561,311. In Germany September 20,

8 Claims. (Cl. 92-3) I have filed application in Germany Sept. 20, lulose may be produced according to any suitable 1930. method, as for instance by treating the crude This invention has reference to improvements cellulose with formaldehyde and acid with or in the manufacture of cellulose products having without other additions, simultaneously or suchigh wet strength which will resist even rough cessively and by exposing it to the action of high 5 usage in the moist condition, as for instance in temperatures. the manufacture of paper towels and the like, In accordance with this invention and by way and it is intended to devise means of manufacof exemplification I may for instance make use turing a better product than generally obtainof a mixture of four parts moisture-proof cellulose 10 able heretofore and to also simplify the process and one part elastic, but not moisture-proof cel- 10 of manufacture of such products. In the various lulose and by this means a kind of paper may be methods suggested by the prior art of manufacobtained which is adaptedto absorb or suckturing water-proof or moisture-proof cellulose up moisture, and which is not brittle and liable to products their water-resisting or water repelling rupture, and which is still sufficiently moistureproperties were ordinarily produced by treating proof to resist disintegration and falling apart and 15 the raw material or the products themselves durflowing away of the fibers when in the moist ing or at the end of the manufacturing process condition, so that it is well adapted for the manuwith water repelling substances with which they facture of handkerchiefs and towels from celwere impregnated, or with certain chemical lulose. In this manneritis also possible to obtain agents, such asacids for instance, and preferably moisture-proof card-board by the employment 20 at an increased temperature. of moisture-proof and of non-moisture-proof or Now, with these-previous methods there is the only slightly moisture-proof crude cellulose. By difficulty that the fibers of the water-proof celthis means thick, bulky articles, such as cellulose lulose products have lost their imbibing or waterartificial wood which are otherwise only superabsorbing qualities, and in view thereof it is one 'fically and unsatisfactorily treated, may be sub- 25 of the important objects of this invention to obmitted to the method of this invention and may tain moisture proof articles which, while being have a highly efficient degree of moisture-proof adapted to absorb moisture and being free from qualities imparted to them, inasmuch as the crude water-repelling qualities will not become disincellulose becomes intimately mixed with the tegrated and will not become flabby or soft or chemical agents on which the moisture-proof 0 collapse and lose their stiffness, when they are quality depends, so that a final product is obexposed to moisture during usage; These and tained of uniform moisture-proof condition similar requirements are of importance for inthroughout. stance in the case of paper handkerchiefs, paper By a suitable selection of the proportions of towels and of similar paper articles which would the mixture of moisture-proof and of non-mois- 35 otherwise be unsuitable for use. It has been asture-proof cellulose in the crude condition the certained that it is not possible to so adjust the degree of resistance against moisture of the final moisture resisting qualities of marketable paper products may be suitably adjusted. Instead of or of other finished cellulose products, as for innon-moistureeproof crude cellulose the moisturestance by treatment with formaline and acid, proof crude cellulose used may alsobemixed with 40 as to prevent such products from becoming at the substances which facilitate the further treatsame time brittle and liable to rupture. ment thereof or which are such as not to with- In accordance with this invention however it stand the chemical agents and high temperatures has become possible to manufacture cellulose e p oyed in the moisture-p 0 the 5 products which have both flexibility and high final product, such as dyes, colors, glue or the wet strength, by employing a treatment which, like. Afurther importa t advantage of t e M instead of converting the finished cellulose ess according to this invenliifln is presented by products into moisture-proof compounds, makes the fact that the procedures dealing with the use of moisture-proof raw material, a miX- subsequent treatment of the finished cellulose 60 m of moisture-proof cr d 11 1 ith are not interfered with by the necessity of efcellulose material of other suitable substances fecting the moisture-9100f treatment which y and possessing none or only limited moisturemay be carried out in a much simpler and less proof qualities being used for instance for expensive manner in the works dealing with the the manufacture of the desired cellulose products, a u cture of cru 8 11 The moisture-proof condition of the crude cel-. T e m ho according to this i vfi n m y E5 for instance be carried out as follows:A suitable kind of cellulose in the crude condition and obtained by the ordinary methods is impregnated with a mixture of 100 parts formaldehyde of 40 percent and 2 parts concentrated nitric acid and intimately mixed therewith. It is then squeezed out and is dried at 120 degrees centigrade upon a heated support. The crude cellulose thus obtained which is proof against moisture is mixed with untreated crude cellulose in the proportion of 4:1, so that a uniform mixture is obtained which is then worked into paper, card-board, artificial wood and other cellulose products in the usual manner.

It should also be pointed out that the scope of the invention is not limited to the particular exemplification herein described as an illustration of its principles, and modifications and changes are possible within the ambit of the claims hereinafter appended.v

I claim:

1. The method of manufacturing cellulose products having high wet strength, which comprises treating crude cellulose with about 40 percent formaldehyde with a limited percentage of concentrated nitric acid, removing the excess of treating liquid, drying the treated cellulose at about 120 degrees C., mixing an excess thereof with untreated crude cellulose and obtaining cellulose articles from said mixture.

2. A process for the production of wet-proof cellulose products which are capable of being wetted and which are absorbent but which do not disintegrate or fray when they become wet, said process comprising providing as initial material about four parts of raw cellulose which has been rendered perfectly wet-proof by treatment with formaldehyde, acid and heat and mixing therewith one part of substantially non-wet-proof cellulose material.

3. That process of preparing cellulose for the manufacture of paper towels and other wet-proof products and which consists in treating raw cellulose with a mixture of formaldehyde and nitric acid exposing said mass to the action of heat at substantially 120 C., and mixing with the treated cellulose a quantity of raw untreated cellulose.

4. That process of preparing cellulose for the manufacture of paper towels and other wet-proof products and which consists in treating raw cellulose with a mixture of formaldehyde and nitric acid exposing said mass to the action of heat at substantially 120 C., and mixing with the treated cellulose a quantity of raw untreated cellulose in the proportion of four parts treated and one part of untreated cellulose.

5. That step in the process of preparing a wetproof cellulose product which consists in treating raw cellulose with a mixture of formaldehyde and concentrated nitric acid exposing said mass to the action of heat at substantially 120 C.

6. That step in the process of preparing a wetproof cellulose product which consists in mixing with raw cellulosean excess of a mixture of substantially one hundred parts of forty percent formaldehyde and two parts of concentrated nitric acid, expressing the excess formaldehyde and acid to partially dry the mass, and exposing the mass to heat at temperature of substantially 120 C.

'7. A process for the production of cellulose products having high wet strength comprising rendering raw cellulose capable of high wet strength by treating said raw cellulose with formaldehyde and acid in the'presence of heat and admixing therewith a cellulose material having substantially no wet strength.

8. A process for the production of cellulose products having high wet strength comprising rendering raw cellulose capable of high wet strength by treating said raw cellulose with formaldehyde and acid at a temperature of substantially 120 C. and admixing therewith a cellulose material having substantially no wet strength.

JULIUS KANTOROWICZ. 

